Question 1

Which molecule enters the citric acid cycle by combining with oxaloacetate to form citrate?

Accepted Answer

Acetyl CoA

Question 2

What is the primary function of the electron transport chain (ETC) in cellular respiration?

Accepted Answer

To create a proton gradient across the inner mitochondrial membrane

Question 3

Which of the following best describes the fate of NADH and FADH2 produced in the citric acid cycle?

Accepted Answer

They are oxidized in the electron transport chain, donating electrons to generate a proton gradient.

Question 4

If a mutation caused the c12 ring of ATP synthase to have a basic residue instead of an acidic one, what would most likely happen?

Accepted Answer

ATP synthesis would immediately and permanently stop.

Question 5

How many molecules of ATP are produced from one molecule of NADH via the electron transport chain?

Accepted Answer

$$3$$

Question 6

Which of the following is a direct result of creating pores in the inner mitochondrial membrane?

Accepted Answer

Leakage of hydrogen ions

Question 7

Which step in the citric acid cycle is most likely to be allosterically regulated by ATP?

Accepted Answer

The conversion of oxaloacetate and acetyl CoA to citrate

Question 8

What is the net yield of ATP (or GTP), NADH, and FADH$$_2$$ from one turn of the citric acid cycle per pyruvate molecule?

Accepted Answer

$$1$$ ATP (or GTP), $$3$$ NADH, $$1$$ FADH$$_2$$

Question 9

Which of the following statements about the citric acid cycle is correct?

Accepted Answer

It regenerates oxaloacetate at the end of each cycle.

Question 10

Why does the addition of any one of the eight carboxylic acids of the citric acid cycle to a cell increase the rate of cellular respiration?

Accepted Answer

It replenishes intermediates, allowing the cycle to proceed more rapidly.

Question 11

Which of the following best explains why the electron transport chain is located in the inner mitochondrial membrane?

Accepted Answer

The inner membrane allows for the establishment of a proton gradient necessary for ATP synthesis.

Question 12

If oxygen is not available as the terminal electron acceptor, what is the most likely consequence for the electron transport chain?

Accepted Answer

The electron transport chain will stop, and ATP production by oxidative phosphorylation will cease.

Question 13

Which of the following is the most common type of enzyme found in the citric acid cycle?

Accepted Answer

Dehydrogenase

Question 14

A patient is found to have a defect in the protein complexes of the electron transport chain. Which of the following would you expect to observe?

Accepted Answer

Decreased ATP production and increased NADH levels

Question 15

Which molecule is the most oxidized form in the citric acid cycle?

Accepted Answer

Oxaloacetate

Question 16

What is the maximum observed number of ATP molecules generated from one molecule of glucose during cellular respiration?

Accepted Answer

$$29$$

Question 17

Which of the following best describes the role of ATP synthase in the mitochondrion?

Accepted Answer

It uses the proton-motive force to synthesize ATP from ADP and inorganic phosphate.

Question 18

Which of the following statements about the regulation of the citric acid cycle is correct?

Accepted Answer

ATP acts as an allosteric inhibitor of the cycle.

Question 19

In prokaryotes, where does the oxidation of NADH and FADH$$_2$$ occur?

Accepted Answer

Plasma membrane

Question 20

Which of the following best explains why the addition of pyruvate or acetyl CoA to a cell results in the conversion of the most oxidized carboxylic acid to the most reduced carboxylic acid?

Accepted Answer

They provide substrates that drive the citric acid cycle forward, reducing intermediates.

Citric Acid Cycle and Electron Transport Chain: Study Notes for General Biology

Guida di studio - Domande di pratica

Study guide - Flashcard